BUG: KASAN: double-free or invalid-free in io_req_caches_free.constprop.0+0x3ce/0x530 fs/io_uring.c:8709
Workqueue: events_unbound io_ring_exit_work
Call Trace:
[...]
__cache_free mm/slab.c:3424 [inline]
kmem_cache_free_bulk+0x4b/0x1b0 mm/slab.c:3744
io_req_caches_free.constprop.0+0x3ce/0x530 fs/io_uring.c:8709
io_ring_ctx_free fs/io_uring.c:8764 [inline]
io_ring_exit_work+0x518/0x6b0 fs/io_uring.c:8846
process_one_work+0x98d/0x1600 kernel/workqueue.c:2275
worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
kthread+0x3b1/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Freed by task 11900:
[...]
kmem_cache_free_bulk+0x4b/0x1b0 mm/slab.c:3744
io_req_caches_free.constprop.0+0x3ce/0x530 fs/io_uring.c:8709
io_uring_flush+0x483/0x6e0 fs/io_uring.c:9237
filp_close+0xb4/0x170 fs/open.c:1286
close_files fs/file.c:403 [inline]
put_files_struct fs/file.c:418 [inline]
put_files_struct+0x1d0/0x350 fs/file.c:415
exit_files+0x7e/0xa0 fs/file.c:435
do_exit+0xc27/0x2ae0 kernel/exit.c:820
do_group_exit+0x125/0x310 kernel/exit.c:922
[...]
io_req_caches_free() doesn't zero submit_state->free_reqs, so io_uring
considers just freed requests to be good and sound and will reuse or
double free them. Zero the counter.
Reported-by: syzbot+30b4936dcdb3aafa4fb4@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 41be53e94fb04 ("io_uring: kill cached requests from exiting task closing the ring")
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
fs/io_uring.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 1501f20fde84..47f3968b8272 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8704,9 +8704,11 @@ static void io_req_caches_free(struct io_ring_ctx *ctx, struct task_struct *tsk)
mutex_lock(&ctx->uring_lock);
- if (submit_state->free_reqs)
+ if (submit_state->free_reqs) {
kmem_cache_free_bulk(req_cachep, submit_state->free_reqs,
submit_state->reqs);
+ submit_state->free_reqs = 0;
+ }
io_req_cache_free(&submit_state->comp.free_list, NULL);
--
2.24.0
